Ballast tamping tool for mobile tamper



Nov. 25, 1969 PLASSER ET 3,479,965

BALLAST TAMPING TOOL FOR MOBILE TAMPER Filed June 19, 1968 2 Sheets-Sheet 1 .5 13-; l E 1.2-3; E

INVENTOR.

Nov. 25, 1969 PLASSER- 3,479,965

BALLAST TAMPING TOOL FOR MOBILE TAMPER Filed June 19, 1968 2 Sheets-Sheet 2 E :LETJZ I N VEN TORS.

AGENT United States Patent US. Cl. 104-12 Claims ABSTRACT OF THE DISCLOSURE In a mobile track tamper wherein vibratory tamping tools are vertically immersed into the ballast and the immersed tools are moved in a plane parallel to the track to tamp the ballast, the tool shafts carry a ballast tamping plate at their lower ends, which is relatively thin and extends vertically to the ballast for penetration into the ballast between ballast rocks, the cross section of the plate in a plane perpendicular to the shaft being substantially uniform throughout at least most of the length of the plate and being sinuous so that the plate surface concavities conform to the average surface curving of the ballast rocks.

REFERENCE TO COPENDING APPLICATION This is a continuation-in-part of our copending application Ser. No. 575,043, filed Aug. 25, 1966 and now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to improvements in tamping tools used for tamping the ballast of a railroad bed, which comprise a shaft and a ballast tamping plate fixed to the lower end of the shaft.

Such tamping tools are used in the well known mobile tempers, such as disclosed in our US. Patent No. 2,876,- 709, for example, wherein the shaft serves to impart to the tamping tools a reciprocating motion and the tamping plates exert a pressure on an area of the ballast to be tamped when pairs of cooperating tamping tools are moved together.

When the conventionally flat tamping plates are to be immersed into a ballast of relatively large rocks, difliculties are frequently encountered and it is not always possible to attain the desired immersion depth promptly because considerable resistance to the downward movement of the tools is offered by the large rocks of the ballast. Thus, considerable downward pressure must be exerted to permit the flat tamping plates to penetrate through the ballast to the desired depth and to move large rocks out of the straight downward path of the tamping plates, requiring large power frequently exce'eding that of the weight of the tamping tool carrier and its tamping tools. This has caused the' tamping tools to find their desired maximum tamping depth only slowly during the tamping operation and under the influence of the vibratory movement of the tools. This produces not only an inferior tamping quality but also causes losses of time and efficiency.

Furthermore, when the flat plates are then pulled out of the tamped ballast, they often push ballast rocks out of the way of their path of movement and thus reduce some of the tamping effect.

In addition, when flat tamping plates are used in such apparatus, ballast rocks tend to escape laterally as tamping pressure is exerted thereon in a plane parallel to the track, thus reducing the tamping effect.

Finally, in more recently devoloped track tampers, the tools of two adjacent pairs of cooperating tamping tools are immersed adjacent to each other in the same space between two ties. In this case, penetration of the tamping tool plates in the ballast in this narrow space has been found to be particularly difiicult with fiat plates.

It is one primary object of the present invention to overcome these and other disadvantages by providing tamping plates shaped to reduce the resistance encountered during their vertical movement through the ballast to a minimum.

It is another object of this invention to avoid the lateral escape of ballast rocks from the tamping plates during their tamping movement.

These and other objects are accomplished according to the invention with a tamping tool which comprises a shaft having a lower end, and a ballast tamping plate fixed to the lower shaft end. The tamping plate is relatively thin and its cross section in a plane perpendicular to the shaft is substantially uniform throughout at least most of its length and sinuous, thus defining concavities conforming to the average surface curving of the ballast rocks. Such a plate readily penetrates through the ballast between the ballast rocks, with a minimum displacement of rocks during vertical movement of the tamping tool, thus reducing the required penetrating power of the tamping tool as well as the disturbance of the tamped ballast during withdrawal of the tool to a minimum.

The tamping tool shafts are mounted on a mobile track tamper for vertical movement through the ballast and for movement in a plane parallel to the track.

When the tamping plate is fixed to the lower end of the shaft at a concavity of the plate, the shaft, too, will encounter minimum resistance during penetration of the ballast.

In accordance with another preferred embodiment, ballast penetration is further enhanced by tapering the shaft and the tamping plate toward the lower edge of the plate. This tapering may be in respect of the thickness of the shaft and plate, and/or in respect of the width of the plate whereby the lower edge of the plate is shorter than the upper edge, thus imparting the shape of a pick to the tamping tool. Such a tapered lower tamping plate edge will be like a toothed cuttingedge penetrating the ballast and greatly facilitating movement therethrough.

BRIEF DESCRIPTION OF DRAWING The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of preferred embodiments thereof, taken in conjunction with the accompanying drawing wherein.

FIG. 1 is a front view of a tamping tool according to the invention;

FIG. 2 is a side view of the tamping tool;

FIG. 3 is a section along line IIIIII of FIG. 1;

FIG. 4 is a top view schematically showing the arrangement of groups of such tamping tools alongside two track ties;

FIGS. 5 and 6 are top views illustrating the penetration of tamping tools between the rocks ofthe ballast;

FIG. 7 is a fragmentary side view of a mobile track tamper carrying tamping tools with plates shapedaccording to the invention; and

FIG. 8 is a view similar to that of a modified tamping tool.

3 DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawing, and first to FIGS. 1 to 3, there is shown a tamping tool shaft 2 having a relatively thin ballast tamping plate 1 fixed to its lower end. As can be seen from FIG. 3, the cross section of the tamping plate in a plane perpendicular to the shaft is substantially uniform and sinuous so that the plate has a concavity to which the tamping tool shaft 2 is fixed. The plate has a pair of convex curves adjacent the shaft on the plate surface to which the shaft is fixed, and two lateral edges projecting in a direction opposite to the shaft. The projecting plate edges make it possible to encompass a larger area of the ballast and thus to compact the bed with greater efliciency because the projecting edges will prevent a lateral displacement of the ballast away from the tamping plates while the same are moved together during the tamping operation. Of course, as can be seen from FIG. 6, the plate may be wider and have more than two convex sections facing the shaft.

FIG. 2 shows the shaft and the tamping plate tapering in thickness toward the lower edge of the plate. In this embodiment, the lower edge will be a toothed cutting edge.

The. embodiment of FIG. 8 shows a tamping plate 1a which tapers from a wider upper edge to a narrower lower edge in the direction of the length of the plate, thus imparting the shape of a pick or spade to the tamping tool plate.

As will be appreciated from FIGS. and 6, tamping the approximate shape shown in FIG. 3 being particularly useful for ballast with relatively large rocks 6 While the plate 1 is better adapted for ballast with relatively small rocks 6'.

FIG. 4 illustrates an arrangement of two groups of two pairs 3, 3' and 4, 4' of tamping tools which are immersed in the ballast, with the adjacent ties 5 and 5' positioned intermediate the pairs of a respective one of the groups. Tamping is accomplished in the conventional manner by moving the tools of each pair together toward the intermediate tie, with the adjacent tamping tools 3' 4 of the pairs of tools immersed in the same ballast space between ties 5, 5'. As disclosed in our US. Patents No. 3,372,651 filed Mar. 19, 1965, and No. 3,357,366 filed Feb. 17, 1966, this arrangement has the considerable adyantage of enabling tamping of two ties simultaneously; However, when several tamping tools are immersed in the same ballast space simultaneously, the resistance to their penetration into the ballast is further increased so that the shape of the tamping plates according to the invention is particularly useful in tamping tools of such machines.

FIG. 7 illustrates a mobile track tamper of the type disclosed and claimed in our Patent No. 3,372,651. It includes a tamping tool carrier 26 slidably supported on posts 27, 27 mounted in carriage frame 28 so that the tamping tools may be vertically moved in respect of ballast 25. Cam shaft 14 is supported on carrier 26, the shaft axis being parallel to ties 5, 5' supporting the rails 13 of the track upon which the carriage of the tamper travels. Upon rotation, shaft 14 imparts a vibratory motion to tamping tool mounting arms 15, 15 so that the tamping tools are vibrated during tamping. The two pairs of tamping tools 11, 11 and 12, 12 are respectively pivotally connected at their upper ends 6 to the outer ends of mounting arms 15, 15. Intermediate their ends, each tamping tool is linked to a pivot 17, which enables the tamping tools to be reciprocated in a plane parallel to the track.

In the illustrated position of the tamping tool carrier,

tamper is moved on rails 13 to the next adjacent pair the tamping tools have been immersed into the ballast of ties, and the operation is repeated.

The tamping tools are connected at pivots 17 to piston rods 18 which are reciprocable in the direction of the track. Each rod carries piston 19 at its inner end, both pistons of each pair of tools gliding in common cylinder 20, 20 and thus dividing each cylinder into two outer chambers and a central chamber. When hydraulic pressure fluid is directed through conduits 21, 21 into the outer chambers of each cylinder, pistons 19 move towards each other and thus close the tamping plates to effect the tamping of the ballast rocks. When pressure fluid, for instance compressed air, is applied through conduit 22 to the central chamber of the cylinders, the pistons and the tamping tools are moved apart.

Furthermore, as FIG. 4 shows, tamping tool plates of sinuous cross section may be so staggered in the direction of extension of the ties, i.e. transversely of the track, that a convex section of one tamping tool plate faces a concave section of an adjacent plate. Thus, two adjacent tools may have the back sides of their tamping plates very close together when the tamping tools are moved apart to the maximum extent. This makes maximum use of the limited space between the ties.

If, as indicated in broken lines in FIG. 4, the lateral edges of the tamping plates project considerably beyond the plane of the plate, the ballast area compacted by the tools may be increased considerably.

While the invention has been described in connection with certain now preferred embodiments, it will be clearly understood that many variations and modifications may occur to those skilled in the art, particularly after benefiting from the present teaching, without departing from the spirit and scope of this invention.

We claim:

1. In a mobile track tamper comprising a vibratory ballast tamping tool mounted for vertical movement into and out of the ballast and for movement in a plane parallel to the track in the ballast, the tamping tool having a shaft with a lower end and a relatively thin ballast tamping plate fixed to the lower shaft end and extending vertically to the ballast, a cross section of the plate in a plane perpendicular to the shaft being substantially uniform throughout at least most of its length, the improvement of the cross section being sinuous and the plate defining concavities along the length thereof which conform to the average surface curving of the ballast rocks.

2. In the mobile track tamper of claim 1, wherein the tamping tool plate tapers along its length from an upper to a lower edge, the lower edge of the plate being narrower than the upper edge.

3. In the mobile track tamper of claim 1, the ballast tamping tool plate having sinuous curves alternating on opposite sides of a median plane extending laterally of the shaft and two lateral edges projecting on the same side of the. plane and opposite to the side of the plane to which the shaft is fixed.

4. In the mobile track tamper of claim 3, a pair of said tamping tools, said tools having pivot support remote from the lower ends, means is provided for reciprocating said shafts about the pivot supports towards and away from each other in a direction perpendicular to the plane of the plates, and said two lateral edges of the tamping tool plates of said pair of tools facing each other.

5. In the mobile track tamper of claim 1, two pairs of said tamping tools, said tools having pivot supports remote from the lower ends, means is provided for reciprocating the shafts of the tools of each pair about the pivot supports towards and away from each other in a direction perpendicular to the plane of the plates, and adjacent ones of the tools of each pair being mounted for immersion in an interspace between two adjacent ties of the track, the adjacent pairs of tamping tools being staggered in the direction of extension of the ties transversely of the track, the sinuous tamping tool plates consisting of alternating concave and convex surface portions, and a concave surface portion of the tamping tool plate of one of the adjacent tools facing a convex surface portion of the adjacent tool.

6. A tool for compacting the rocks of ballast, compris ing an elongated tool shaft, a ballast tamping plate lying against the lower end portion of said shaft and atfixed thereto with portions of said plate extending laterally from opposite sides thereof, the cross section of said plate in a plane perpendicular to said shaft having spaced convex portions and intermediate concave portions, the concave portions conforming to the average surface curving of the ballast rocks, and said lower end portion of said shaft lying within an intermediate concave portion.

7. The tool of claim 6, wherein a pair of said concave portions adjacent said last-named intermediate concave portion face in a direction opposite to that of said intermediate concave portion.

8. The tool of claim 6, wherein the cross section of the plate is sinuous.

9. The tool of claim 6, wherein the lower end portion of said shaft and the lower edge of said plate are beveled, with the bevel of one being a continuation of the other.

10. The tool of claim 6, wherein the lower edge of said plate is a saw toothed cutting edge.

References Cited UNITED STATES PATENTS 1,911,966 5/1933 Pickop.

FOREIGN PATENTS 478,243 1/ 1938 Great Britain.

JACOB L. NACKENOFF, Primary Examiner US. Cl. X.R. 94-48 

